The best thing to do first when approached by a LEO in regards to a MWAG call (or anything, really, unless you know you are being stopped for speeding or something like that) is to ask the officer if you are being detained or not. If the officer answers, "No you are not being detained....", regardless of what he finishes that sentence with, politely inform him/her, "Officer, since you are not detaining me, then I will be on my way, thank you." And start to leave.
This settles the very first issue that will come up in court, should you choose or have to go to court. If you are fighting a charge based on the fact that the officer had no lawful reason to detain you, the first issue is whether you were detained or whether you consented to the encounter. Let's say cop stops you for your gun only, and asks you for ID. You don't feel like you can refuse and you give it to him. Now, in court, you will have to prove that a reasonable person would feel like they could not refuse. The cop is going to say, I asked him for ID, I did not demand it, he was free to go at anytime, but he chose, voluntarily, to cooperate and gave me his ID. If the judge believes that, your claim that the officer had no lawful reason to stop you is gone.
Now, if you ask, am I being detained? And if not, you advise the officer that your intention is to leave, and the officer detains you or says you are being detained, the first issue is settled. You did not consent or volunteer to participate in the encounter. Now, instead of the burden of proof being upon you to prove you were detained, the burden of proof now shifts to the officer to prove that he had reasonable and articulable suspicion of a crime for which to detain you. If the court finds that there was no lawful reason for you to be detained to begin with, then everything after that is in your favor. Just like in State v. Casaad that I linked to earlier. There have been many, many, many cases where evidence or the entire case against a person has been tossed out, even when the person was actually guilty, because the officer had no reason to detain the person to begin with.
